Volatile fragrances associated with flowers mediate host plant alternation of a polyphagous mirid bug.

Hongsheng Pan,Livy Williams Iii,Yongjun Zhang,Xiaoling Sun,Kongming Wu,Chunli Xiu,Yanhui Lu,Huihui Geng,Xiaoming Cai,Kris A G Wyckhuys

doi:10.1038/srep14805

Abstract

Apolygus lucorum (Hemiptera: Miridae) is an important insect pest of cotton and fruit trees in China. The adults prefer host plants at the flowering stage, and their populations track flowering plants both spatially and temporally. In this study, we examine whether flower preference of its adults is mediated by plant volatiles, and which volatile compositions play an important role in attracting them. In olfactometer tests with 18 key host species, the adults preferred flowering plants over non-flowering plants of each species. Coupled gas chromatography-electroantennography revealed the presence of seven electrophysiologically active compounds from flowering plants. Although the adults responded to all seven synthetic plant volatiles in electroantennography tests, only four (m-xylene, butyl acrylate, butyl propionate and butyl butyrate) elicited positive behavioral responses in Y-tube olfactometer bioassays. The adults were strongly attracted to these four active volatiles in multi-year laboratory and field trials. Our results suggest that these four fragrant volatiles, which are emitted in greater amounts once plants begin to flower, mediate A. lucorum’s preference to flowering host plants. We proved that the use of commonly occurring plant volatiles to recognize a large range of plant species can facilitate host selection and preference of polyphagous insect herbivore.

Highlights

Plant species Agastache rugosus (Fisch. et Meyer) O. kuntze
For both genders, the magnitude of responses was usually stronger for trials comparing the blank control versus flowering plants than for trials comparing non-flowering plants versus flowering plants (Table 1)
Results of this study are consistent with previous work that indicates that A. lucorum shows a marked preference for host plants at the flowering stage, and that host plant phenology plays an important role in seasonal dispersal between hosts by A. lucorum in agricultural landscapes[23,25,27]

Summary

Introduction

Plant species Agastache rugosus (Fisch. et Meyer) O. kuntze. Artemisia annua L. The role of plant volatiles alone or in combination with insect-derived compounds extends to the trophic level to guide host finding by mirid natural enemies[20,21]. Recent research has revealed that A. lucorum is another polyphagous mirid, with host range exceeding 200 different plant species[24]. It shows a clear preference for plants in reproductive, i.e., flowering stages[25]. We hypothesized that co-occurring plant volatiles emitted at the flowering stage mediate host finding and selection by A. lucorum. We characterized A. lucorum behavioral responses to odors collected from plants at flowering and non-flowering stages for 18 key host plants selected from our previous work[25]. This study should help us to understand the host-plant utilization and alternation by A. lucorum, and the broader interaction between polyphagous mirid bugs and their host plants

Methods

Results

Conclusion